What side effects are expected with the vaccines? (Updated*)

Pfizer-BioNtech

It is important to note that the vaccine cannot give anyone the virus. Sore arm, injection site soreness and/or redness, some experience systemic side effects/immune response like muscle aches, fatigue, low grade fever, some reported a headache. These symptoms are likely only to last 1-2 days, no more than one week and much less severe than actually getting the virus itself. In the Pfizer-BioNTech clinical trial, 77.4% reported at least one systemic reaction during the seven days after vaccination. The frequency of systemic adverse events was higher in the younger age group than the older age group (82.8% vs 70.6%). Within each age group, the frequency and severity of systemic adverse events was higher after dose two than dose one (with the exception of vomiting and diarrhea which were similar between doses and between vaccine and placebo).

Moderna

It is important to note that the vaccine cannot give anyone the virus. Sore arm, injection site soreness and/or redness, some experience systemic side effects/immune response like muscle aches, fatigue, low grade fever, some reported a headache. These symptoms are likely to last 1-2 days, no more than one week and much less severe than actually getting the virus itself. In the Moderna clinical trial, systemic reactions were reported by the majority of vaccine recipients and at higher rates than placebo recipients. The frequency of systemic reactions among vaccine recipients was higher in the younger age group (18-64 yo) than the older age group (81.9% vs 71.9% after dose 2). Within each age group, the frequency and severity of systemic reactions was higher after dose 2 than dose 1. For both age groups, fatigue, headache and myalgia were the most common.

Johnson & Johnson

The most common adverse reactions reported in the clinical trial following administration of the vaccine included injection site pain (48.6%), headache (38.9%), fatigue (38.2%), myalgia (33.2%), and nausea (14.2%). Severe allergic reactions, including one case of anaphylaxis in an ongoing open-label study in South Africa, have been reported following the Janssen COVID-19 vaccine administered in clinical studies.

Additional adverse reactions, some of which may be serious, may become apparent with more widespread use of the Janssen COVID-19 Vaccine.

Not everyone will experience significant side effects from these vaccines. This does NOT mean the vaccine isn’t working. The CDC is actively collecting info about side effects – sign up with V-safe after getting the vaccine and get texts that ask several questions about how you feel. This is part of the ongoing active monitoring for safety.

Sources

Updated: March 1, 2021

ICSI

ICSI